
.header{
    height: 48px;
    background-color: red;
}
.body{
    background-color: #dddddd;
}
.body .menu{
    background-color: green;
    float: left;
    width: 20%;
}
.body .content{
    background-color: darkslategray;
    float: left;
    width: 70%;
}